TWI525662B - Unit for liquid phase epitaxy growth of single crystal silicon carbide and method for liquid phase epitaxy growth of single crystal silicon carbide - Google Patents

Description

Liquid crystal epitaxial growth unit for monocrystalline carbonized niobium and liquid crystal epitaxial growth method for monocrystalline niobium carbide

The present invention relates to a liquid crystal epitaxial growth unit for monocrystalline carbonized niobium and a liquid crystal epitaxial growth method for monocrystalline niobium carbide using the unit.

Tantalum carbide (SiC) is considered to be capable of achieving high temperature resistance, high withstand voltage, high frequency resistance, and high environmental resistance that cannot be achieved with conventional semiconductor materials such as germanium (Si) or gallium arsenide (GaAs). Therefore, tantalum carbide is a semiconductor material which is expected to be a semiconductor material or a high-frequency device for power devices of the next generation.

In the past, as a method of growing monocrystalline niobium carbide, for example, in the following Patent Document 1 and the like, a sublimation recrystallization method (a modified Rayleigh method) is proposed. Here, the Rayleigh method is modified by disposing a seed material composed of monocrystalline niobium carbide in a low temperature side region in a crucible, and disposing a raw material powder containing Si as a raw material in a high temperature side region. Then, after the inside of the crucible is surrounded by an inert gas, the raw material powder disposed in the high temperature side region is sublimated by heating to a high temperature of 1450 ° C to 2400 ° C. As a result, the niobium carbide can be epitaxially grown on the surface of the seed material disposed on the low temperature side region.

However, the modified Rayleigh method is a method of growing crystals of tantalum carbide by setting a temperature gradient in the gas phase. Therefore, when the modified Rayleigh method is used, a large-scale apparatus is required for epitaxial growth of tantalum carbide, and it becomes difficult to control the process of epitaxial growth of tantalum carbide. Therefore, the manufacturing cost of the tantalum carbide epitaxial growth film becomes high. Moreover, in the gas phase, the epitaxial growth of niobium carbide is not balanced. Therefore, in the formed tantalum carbide epitaxial growth film, crystal defects are likely to occur, and in the crystal structure, wrinkles are likely to occur.

As an epitaxial growth method of the ruthenium carbide other than the Raleigh method, for example, Metastable Solvent Epitaxy (Metastable Solvent Epitaxy) which has been proposed in the liquid phase for the epitaxial growth of tantalum carbide in the liquid phase has been proposed. MSE) method.

In the MSE method, a seed material made of crystalline tantalum carbide such as monocrystalline niobium carbide or polycrystalline niobium carbide, and a feed material made of tantalum carbide are, for example, small in a size of 100 μm or less. The phases face each other in the interval and the molten layer of Si is interposed therebetween. Then, the tantalum carbide is epitaxially grown on the surface of the seed material by heat treatment in a vacuum high temperature environment.

This MSE method is considered to be caused by the difference in the chemical potential energy of the seed material and the chemical potential energy of the feed material, and the carbon concentration in the Si molten layer is concentrated to form a tantalum carbide epitaxial growth film. Therefore, unlike the case of using the modified Rayleigh method, it is not necessary to provide a temperature difference between the seed material and the feed material. Therefore, in the case of using the MSE method, it is possible to easily control the epitaxial growth process of the niobium carbide with a simple device, and it is possible to stably form a high-grade niobium carbide epitaxial growth film.

Further, there is an advantage that a tantalum carbide epitaxial growth film can be formed on a seed crystal substrate having a large area, and since the Si molten layer is extremely thin, carbon from the feed material is easily diffused, and it is also possible to make the tantalum carbide The advantage of low temperature in the epitaxial growth process.

Therefore, the MSE method as an epitaxial growth method of monocrystalline niobium carbide is considered to be extremely useful, and research on the MSE method is currently prevailing.

[Previous Technical Literature] (Patent Literature)

Patent Document 1: Japanese Laid-Open Patent Publication No. 2005-97040

Patent Document 2: Japanese Laid-Open Patent Publication No. 2008-230946

As described above, in the MSE method, it is considered necessary to select the feed material and the seed material so that the free energy of the feed material is higher than the free energy of the seed crystal. Therefore, for example, in the above Patent Document 2, it is revealed that the free energy of the feed material and the seed material differs by making the crystal shape of the feed substrate and the seed crystal substrate different. Specifically, when a feed substrate is formed of a polycrystalline 3C-SiC substrate, a seed crystal substrate is formed of a single crystal 4H-SiC substrate having a lower free energy than the 3C-SiC substrate.

Here, the polycrystalline 3C-SiC substrate can be easily fabricated by a CVD method. Therefore, as described in Patent Document 2, by using the 3C-SiC substrate as a feed substrate, the formation cost of the tantalum carbide epitaxial growth film can be suppressed to be low.

However, in a tantalum carbide substrate such as a 4H-SiC substrate or a 3C-SiC substrate, the 3C-SiC substrate has the highest free energy. Therefore, it is considered that the 3C-SiC substrate cannot be used as a seed crystal substrate requiring low free energy. Therefore, in Patent Document 2, a single crystal 4H-SiC substrate which is difficult to manufacture and has a high cost is used as a seed crystal substrate, and the cost of forming a tantalum carbide epitaxial growth layer becomes high.

The present invention has been made in view of the above points, and an object thereof is to reduce the cost required for liquid phase epitaxial growth of monocrystalline niobium carbide.

As a result of intensive research, the present inventors have found that among the polycrystalline carbonized coffins having a crystal polymorph of 3C, there is also a possibility that the melting of the molten layer of the crucible is easy to occur and the melting is not easy to occur. It is suitable for use as a seed crystal when the melting of the molten layer of the crucible is not easy to occur, and the liquid crystal epitaxy of the monocrystalline niobium carbide is suitable for use as a feed material for melting the crucible molten layer. growing up. As a result, the inventors completed the present invention.

That is, the unit for liquid phase epitaxial growth of a monocrystalline niobium carbide according to the present invention is a unit of a seed crystal and a feed material used in a liquid phase epitaxial growth method of monocrystalline niobium carbide. The feed material has a surface layer comprising polycrystalline niobium carbide having a crystalline polymorph of 3C. The feed material is irradiated by X-ray diffraction of the surface layer as a diffraction peak corresponding to a polycrystalline niobium carbide having a crystal polymorph of 3C, and a diffraction peak corresponding to the (111) crystal plane and a corresponding (111) crystal plane can be observed. The diffraction peaks other than the diffraction peaks. The seed crystal has a surface layer containing polycrystalline niobium carbide having a crystal polymorph of 3C. The crystallized material is diffracted by the X-ray of the surface layer as the diffraction peak corresponding to the polycrystalline niobium carbide having a crystal polymorph of 3C, and the first diffraction peak corresponding to the (111) crystal plane can be observed, and no diffraction can be observed. The other one-order diffraction peak corresponding to the diffraction intensity of 10% or more of the diffraction intensity of the first-order diffraction peak of the (111) crystal plane. Therefore, the seed crystal of the unit for liquid phase epitaxial growth of the monocrystalline niobium carbide according to the present invention is relatively inferior to the melting of the tantalum molten layer, and on the other hand, the feed material is opposite to the tantalum molten layer. Melting is relatively easy to produce.

Therefore, liquid phase epitaxial growth of monocrystalline niobium carbide can be suitably performed by using the monocrystalline niobium carbide liquid phase epitaxial growth unit according to the present invention. Further, in the present invention, both the seed material and the feed material have a surface layer containing a polycrystalline niobium carbide having a crystal polymorph of 3C, so that the seed material and the feed material can be respectively CVD (chemical gas) The Chemical Vapor Deposition method is easy and inexpensive to manufacture. Therefore, according to the present invention, for example, the formation cost of the epitaxial growth film of the monocrystalline niobium carbide can be compared with the case where the seed material is a surface layer composed of 4H-SiC or 6H-SiC, and monocrystalline niobium carbide. reduce.

Further, in the case where another diffraction peak having a diffraction intensity corresponding to 10% or more of the diffraction intensity of the first diffraction peak of the (111) crystal plane is not observed, the melting of the tantalum molten layer is It is considered that the degree of exposure of the (111) crystal face which is less likely to be melted in the tantalum molten layer than the other crystal faces is increased. On the other hand, in the case where a diffraction peak other than the diffraction peak of the (111) crystal plane can be observed, the melting of the tantalum molten layer is easy to occur, and it is considered that the (111) crystal plane is The degree of exposure of the crystal face other than the (111) crystal face which is easy to melt the molten layer of the crucible is increased.

Further, according to the present invention, an epitaxial growth film of hexagonal crystal single crystal yttrium carbide having excellent characteristics can be formed. This is because the (111) crystal plane is equivalent to the hexagonal (0001) crystal plane, and the tracking error is likely to occur. As a result, it is considered to be suitable for epitaxial growth of hexagonal crystal single-crystal carbide by using the (111) crystal face to use a plurality of exposed crystal materials.

In the present invention, the "liquid phase epitaxial growth method" means that the molten material is formed in the tantalum molten layer by heating the crystal material and the feed material while being opposed to each other via the tantalum molten layer. Concentration gradient, by means of the concentration gradient, a method for epitaxial growth of monocrystalline niobium carbide on a seed material.

In the present invention, "X-ray diffraction" means diffraction using X-rays (CuKα rays) of 8.48 keV.

In the present invention, the term "feed material" means, for example, a member that supplies a material such as Si, C, or SiC which is a material for epitaxial growth of single crystal cerium carbide. On the other hand, "crystal seed material" means a material which grows on the surface into a single crystal yttrium carbide.

In the present invention, "a diffraction peak can be observed" means that a diffraction peak having a peak intensity corresponding to a peak intensity of 3% or more corresponding to a first-order diffraction peak of the (111) crystal plane is observable.

In the present invention, the "diffraction peak of the corresponding (111) crystal plane" includes a first-order diffraction peak and a high-order diffraction peak corresponding to the (111) crystal plane.

In the X-ray diffraction of the surface layer of the feed material, the first-order diffraction peak corresponding to the (111) crystal plane is the largest of the first-order diffraction peaks corresponding to the polycrystalline niobium carbide of 3C. The main diffraction peak of the diffraction intensity is preferred.

In the X-ray diffraction of the surface layer of the feed material, it is observed that the diffraction peaks other than the diffraction peak corresponding to the (111) crystal plane contain the corresponding (200) crystal plane, (220) crystal plane, And at least one of the (311) crystal faces is preferably a diffraction peak. According to this structure, the epitaxial growth rate of the monocrystalline carbonized niobium can be more effectively improved. It is considered that the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane are likely to cause melting of the (111) crystal facing the tantalum molten layer. From the viewpoint of making the epitaxial growth rate of the monocrystalline niobium carbide more effective, it can be observed in the X-ray diffraction of the surface layer of the feed material, and the winding around the diffraction peak corresponding to the (111) crystal plane is observed. The peak of the radiation is preferably a diffraction peak containing a (200) crystal plane, a (220) crystal plane, and a (311) crystal plane.

In the X-ray diffraction of the surface layer of the feed material, the sum of the intensities of the first diffraction peaks other than the first diffraction peak of the (111) crystal plane is 10% of the sum of the intensity of all the first diffraction peaks. The above is better, preferably 20% or more. According to this configuration, the ratio of the crystal faces other than the (111) crystal plane having a higher reactivity than the (111) crystal plane can be made more. Therefore, the epitaxial growth rate of the monocrystalline niobium carbide can be more effectively improved.

The feed material and the seed material respectively have a polycrystalline niobium carbide surface layer containing a crystal polymorph of 3C, and by the X-ray diffraction of the surface layer, the corresponding (111) crystal plane, (200) crystal plane, (220) can be observed. a crystallized surface and at least one primary diffraction peak of the (311) crystal plane, an average crystallite diameter calculated from at least one of the first-order diffraction peaks of the feed material, Preferably, the average microcrystal diameter calculated by at least one of the diffraction peaks of the material is small. With this structure, the epitaxial growth rate of the monocrystalline niobium carbide can be more effectively improved. This is considered to be the ratio of the grain boundary material to the feed material, and the ratio of the grain boundary which is easily melted to the tantalum melt layer in the surface layer becomes small, so that between the seed material and the feed material The easiness of melting of the crucible molten layer can be changed to a large extent.

The average microcrystal diameter calculated from the first diffraction peak of the polycrystalline niobium carbide of 3C corresponding to the crystal polymorph in the X-ray diffraction of the surface layer of the feed material is 700. The following is better. According to this structure, the epitaxial growth rate of the monocrystalline carbonized niobium can be more effectively improved. It is considered that in the surface layer of the feed material, the ratio of the grain boundary of the polycrystalline niobium carbide crystal having high reactivity is increased, and the melting of the tantalum molten layer on the surface layer of the feed material is likely to change.

Moreover, by the X-ray diffraction of the surface layer of the feed material, the first diffraction peak corresponding to the (111) crystal plane, the corresponding (200) crystal plane, the (220) crystal plane, and the (311) crystal plane can be observed. Preferably, at least one of the diffraction peaks is (I ₁ /I ₀ ) ^-1 ‧D ² is preferably 10 ⁸ or less.

among them,

I ₀ : the total intensity of the first-order diffraction peak corresponding to the (111) crystal plane, and the total intensity of the first-order diffraction peak corresponding to at least one of the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane Sum,

I ₁ : the total intensity of the first-order diffraction peak corresponding to at least one of the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane,

D: an average microcrystal diameter calculated from a primary diffraction peak corresponding to at least one of a (200) crystal plane, a (220) crystal plane, and a (311) crystal plane.

According to this structure, the epitaxial growth rate of the monocrystalline niobium carbide can be more effectively improved. This is because in the surface layer of the feed material, the ratio of the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane which are considered to be relatively high is increased, and the average crystallite diameter becomes small. The reason.

On the other hand, regarding the seed crystal, it is observed in the X-ray diffraction of the surface layer that the average microcrystal diameter calculated from the first diffraction peak corresponding to the polycrystalline niobium carbide having a crystal polymorph of 3C is a ratio 700 Greatly better. According to this structure, the epitaxial growth rate of the monocrystalline carbonized niobium can be more effectively improved. It is considered that in the surface layer of the seed crystal, the proportion of the highly reactive grain boundary of the polycrystalline niobium carbide crystals becomes small, so that the melting of the tantalum molten layer of the surface layer of the seed crystal becomes less likely to occur. The reason.

In the present invention, the "microcrystal diameter" is calculated based on the Hall formula shown by the following formula (1).

Β‧(cosθ)/λ=2η‧(sinθ)/λ+1/ε...(1)

among them,

β: half value width,

θ: Bragg Angle around the ray,

λ: the wavelength of the X-ray used in the measurement,

η: the unevenness value of the crystal,

ε: the average size of the microcrystalline diameter.

Among the (111) crystal faces which can be observed by the X-ray diffraction of the surface layer, the ratio of the alignment angle of 67.5° or more is preferable to the smaller one than the seed crystal. According to this structure, the epitaxial growth rate of the monocrystalline carbonized niobium can be more effectively improved. This is based on the fact that the (111) crystal plane exposed on the (111) crystal plane has a lower degree of stability on the surface with lower stability, and is considered to be a seed material because the feed material becomes higher than the crystal material. The ease of melting of the opposing molten layer between the feed material and the feed material may be greater.

From the viewpoint of more effectively increasing the epitaxial growth rate of the monocrystalline niobium carbide, the ratio of the alignment angle of 67.5° or more in the (111) crystal plane which can be observed by the X-ray diffraction of the surface layer of the feed material is Less than 80% is better. Further, in the (111) crystal plane which can be observed by X-ray diffraction of the surface layer of the seed material, the ratio of the alignment angle of 67.5° or more is preferably 80% or more.

Further, in the feed material and the seed material, by the Reman spectroscopic analysis in which the excitation wavelength is set at 532 nm, it is possible to observe the L0 peak derived from the polycrystalline niobium carbide having a crystal polymorph of 3C in the surface layer. The absolute value of the movement of the L0 peak from 972 cm ^-1 is preferably that the feed material is smaller than the crystal material. In this case, it is difficult to change the melting of the molten layer by the seed material, and on the other hand, the melting of the molten layer of the feed material is likely to occur. As a result, the epitaxial growth film of the monocrystalline niobium carbide can be appropriately formed with a faster growth rate.

Further, when the absolute value of the movement amount of the L0 peak from 972 cm ^-1 is large, the melting of the tantalum molten layer becomes difficult to occur, and it is considered that the internal stress of the surface layer becomes large, and the surface layer is dense. Going higher. On the other hand, when the absolute value of the amount of movement is small, it is easy to melt the crucible molten layer, and it is considered that the internal stress of the surface layer is small, and the denseness of the surface layer is lowered. Further, by the improvement of the denseness of the surface layer of the seed material, most of the crystal faces exposed on the surface of the seed material are considered to contribute to the formation of a shape similar to the (0001) crystal plane of the hexagonal crystal.

Further, in the present invention, the "L0 peak derived from polycrystalline niobium carbide" means a peak derived from a longitudinal optical mode in an optical mode of vibration between two atoms of Si-C in a lanthanum carbide crystal. In the case of the usual 3C polymorph, a peak appears at 972 cm ^-1 .

From further improve the epitaxial growth of the monocrystalline silicon carbide of the viewpoint, L0 peak in the feed material from the absolute value of the amount of movement of 972cm ^-1 is preferably less than 4cm ^-1. Seed material from the absolute value of the movement amount of a peak L0 is 972cm ^-1 or more is preferably at 4cm ^-1.

Further, the half value width of the L0 peak in the feed material is preferably 7 cm ^-1 or more. The half value width of the L0 peak in the seed crystal is preferably 15 cm ^-1 or less.

Further, when the half value width of the L0 peak in the feed material is 7 cm ^-1 or more, the liquid crystal epitaxial growth rate of the monocrystalline niobium carbide can be further increased, because the half value width of the L0 peak is larger, and the polycrystalline carbonization in the surface layer The crystallinity of the crucible is lowered, or the impurity concentration is increased, so that it is considered that the change from the surface layer is likely to occur. On the other hand, when the half value width of the L0 peak in the seed material is 15 cm ^-1 or less, the liquid crystal epitaxial growth rate of the monocrystalline niobium carbide can be further improved, because the half value width of the L0 peak is smaller, and the surface layer is more The crystallinity of the crystalline niobium carbide is increased, or the impurity concentration is lowered, so that it is considered that the change from the melting of the surface layer is not easy to occur.

In at least one of the feed material and the seed material, it is preferable that the surface layer contains polycrystalline niobium carbide having a crystal polymorph of 3 C as a main component, and substantially, the polycrystalline niobium carbide having a crystal polymorph of 3 C is formed. good. According to this structure, the epitaxial growth rate of the monocrystalline carbonized niobium can be more effectively improved.

In the present invention, the "main component" means a component containing 50% by mass or more.

In the present invention, "substantially, a polycrystalline niobium carbide having a crystal polymorph of 3C" means that the crystal polymorph is a component other than the polycrystalline niobium carbide which does not contain 3C except for the impurities. In general, the impurities contained in the case of "substantially formed by polycrystalline niobium carbide having a crystal polymorph of 3 C" are 5% by mass or less.

At least one of the feed material and the seed material may be provided with a support material and a polycrystalline niobium carbide film formed on the support material to form a surface layer. In this case, the thickness of the polycrystalline niobium carbide film is preferably in the range of 30 μm to 800 μm.

Further, at least one of the feed material and the seed material may be composed of a polycrystalline carbonized niobium containing a polycrystalline niobium carbide having a crystal polymorph of 3C.

The liquid crystal epitaxial growth method of the single crystal cerium carbide according to the present invention is a liquid crystal epitaxial growth method using a single crystal cerium carbide liquid crystal growth unit according to the present invention. The liquid crystal epitaxial growth method of the single crystal yttrium carbide according to the present invention is carried out by heating the surface layer of the seed material and the surface layer of the feed material relative to each other via the ruthenium molten layer. Monocrystalline niobium carbide is epitaxially grown on the surface layer of the seed material.

According to this method, the epitaxial growth film of the monocrystalline niobium carbide can be formed at a low price. Moreover, it is not always necessary to set a temperature difference between the seed material and the material. Therefore, with a simple device, not only the epitaxial growth process of the monocrystalline carbonized niobium can be easily controlled, but also the epitaxial growth film of the high-grade single crystal niobium carbide can be stably formed.

According to the present invention, the necessary cost in liquid phase epitaxial growth of monocrystalline niobium carbide can be reduced.

Hereinafter, an example of a preferred embodiment of the present invention will be described, but the following embodiments are merely illustrative. The present invention is not limited to the following embodiments.

Fig. 1 is a schematic view for explaining a method of epitaxial growth of monocrystalline niobium carbide in the present embodiment.

In the present embodiment, an example of forming an epitaxial growth film of monocrystalline niobium carbide by the MSE method will be described.

In the present embodiment, as shown in Fig. 1, a seed crystal substrate 12 as a seed crystal material and a feed substrate 11 as a feed material are used in a container 10 for a liquid crystal epitaxial growth unit of single crystal 14. The main surface 12a of the seed substrate 12 and the main surface 11a of the feed substrate 11 are disposed so as to face each other across the raft. In this state, the seed substrate 12 and the feed substrate 11 are heated to melt the raft. By doing so, the seed substrate 12 and the feed substrate 11 are in a state of being opposed to each other via the tantalum molten layer 13. By maintaining this state, raw materials such as tantalum, carbon, and tantalum carbide are melted from the seed crystal substrate 12 side to the tantalum molten layer 13. Thereby, a concentration gradient is formed in the crucible melt layer 13. As a result, monocrystalline niobium carbide is epitaxially grown on the main surface 12a of the seed crystal substrate 12, and a monocrystalline niobium carbide epitaxial growth film 20 is formed. Further, the thickness of the tantalum molten layer 13 is extremely thin, and may be, for example, about 10 μm to 100 μm.

Fig. 2 is a schematic cross-sectional view showing the feed substrate 11. Fig. 3 is a schematic cross-sectional view showing the seed substrate 12. Each of the feed substrate 11 and the seed crystal substrate 12 has a surface layer containing polycrystalline niobium carbide having a crystal polymorph of 3C. Specifically, as shown in FIGS. 2 and 3, in the present embodiment, the feed substrate 11 and the seed substrate 12 each have support members 11b and 12b made of graphite, and polycrystalline niobium carbide films 11c and 12c. . The support materials 11b and 12b made of graphite have high heat resistance which can sufficiently withstand the epitaxial growth process of niobium carbide. Further, the support members 11b and 12b made of graphite have a thermal expansion coefficient similar to that of the monocrystalline niobium carbide epitaxial growth film 20. Therefore, the niobium carbide epitaxial growth film 20 can be suitably formed by using the support materials 11b and 12b made of graphite.

Further, specific examples of the graphite include natural graphite, artificial graphite, petroleum coke, coal coke, pitch coke, carbon black, mesocarbon (mesocarbon), and the like. The manufacturing method of the support material 12b by the graphite, for example, the manufacturing method of the Unexamined-Japanese-Patent No. 2005-132711.

The polycrystalline niobium carbide films 11c and 12c are formed so as to cover the main surface and the side surface of the supporting members 11b and 12b. The polycrystalline niobium carbide films 11c and 12c contain polycrystalline niobium carbide. The surface layer of the feed substrate 11 or the seed substrate 12 is formed by the polycrystalline niobium carbide films 11c and 12c. Further, the polycrystalline niobium carbide films 11c and 12c in the present embodiment preferably contain polycrystalline 3C-SiC as a main component, and are preferably formed of polycrystalline 3C-SiC. That is, in the present embodiment, the surface layer of each of the feed substrate 11 and the seed crystal substrate 12 is preferably composed of polycrystalline 3C-SiC as a main component, and substantially composed of polycrystalline 3C-SiC. It is better. By doing so, the growth rate of the epitaxial growth film 20 of the monocrystalline carbonized niobium can be increased.

The thicknesses t11 and t12 of the polycrystalline niobium carbide films 11c and 12c are preferably in the range of 30 μm to 800 μm, more preferably in the range of 40 μm to 600 μm, and even more preferably in the range of 100 μm to 300 μm. When the thicknesses t11 and t12 of the polycrystalline niobium carbide films 11c and 12c are too thin, when the monocrystalline niobium carbide epitaxial growth film 20 is formed, the support material 12b made of graphite is exposed, and the support material 11b is derived from the support material 11b. When 12b is melted and a suitable monocrystalline niobium carbide epitaxial growth film 20 cannot be obtained, on the other hand, when the thicknesses t11 and t12 of the polycrystalline niobium carbide films 11c and 12c are too thick, there is a polycrystalline niobium carbide. The film 12c is liable to be cracked.

The method for forming the polycrystalline niobium carbide films 11c and 12c is not particularly limited. The polycrystalline niobium carbide film 12c can be formed, for example, by a CVD (Chemical Vapor Deposition) method, a sputtering method, or the like. In particular, in the present embodiment, since the polycrystalline niobium carbide films 11c and 12c are made of polycrystalline 3C-SiC, the dense polycrystalline niobium carbide films 11c and 12c can be easily and inexpensively formed by the CVD method.

The polycrystalline niobium carbide film 11c constituting the surface layer of the feed substrate 11 is diffracted by X-rays as a diffraction peak corresponding to polycrystalline 3C-SiC, and the diffraction of the corresponding (111) crystal plane can be observed. The peak is observed and the diffraction peak other than the diffraction peak corresponding to the (111) crystal plane is observed. The polycrystalline niobium carbide film 11c is diffracted by X-rays as a diffraction peak corresponding to polycrystalline 3C-SiC, so that the diffraction peak of the corresponding (111) crystal plane can be observed, and the ratio is observed. It is preferable to correspond to the primary diffraction peak of the crystal plane other than the (111) crystal plane corresponding to the 10% intensity of the first-order diffraction peak of the (111) crystal plane.

As the diffraction peak corresponding to the polymorphic 3C-SiC, the diffraction peak corresponding to the (111) crystal plane, the diffraction peak corresponding to the (200) crystal plane, and the diffraction peak corresponding to the (200) crystal plane are as shown in Table 1 below. The diffraction peak corresponding to the (220) crystal plane and the diffraction peak corresponding to the diffraction peak of the (311) crystal plane. Therefore, in particular, the polycrystalline niobium carbide film 11c is diffracted by X-rays, and as a diffraction peak corresponding to polycrystalline 3C-SiC, the diffraction peak of the corresponding (111) crystal plane can be observed, and At least one of the diffraction peaks corresponding to the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane is observed.

On the other hand, the polycrystalline niobium carbide film 12c constituting the surface layer of the seed crystal substrate 12 is diffracted by X-rays as a diffraction peak corresponding to polycrystalline 3C-SiC, and the corresponding (111) crystal plane can be observed. The peak is diffracted once, and the other diffraction peak having a diffraction intensity of 10% or more corresponding to the diffraction intensity of the first diffraction peak of the (111) crystal plane cannot be observed.

Therefore, the seed crystal 12 is relatively unfavorable for the melting of the tantalum molten layer 13, and on the other hand, the melt of the feed material 11 against the tantalum molten layer 13 is relatively easy to occur. Therefore, by using the monocrystalline niobium carbide liquid phase epitaxial growth unit 14 of the present embodiment, the liquid crystal epitaxial growth film 20 of the monocrystalline niobium carbide can be appropriately formed. Further, both the seed crystal 12 and the feed material 11 have a surface layer containing a polycrystalline niobium carbide having a crystal polymorph of 3C. Therefore, the seed crystal 12 and the feed material 11 can be easily and inexpensively produced by the CVD method, respectively. Therefore, the formation cost of the epitaxial growth film 20 of the monocrystalline niobium carbide can be lowered as compared with the case where the feed material is formed to have a surface layer formed of 4H-SiC or 6H-SiC or monocrystalline niobium carbide.

At the same time, when the other diffraction diffracting peak having a diffraction intensity of 10% or more corresponding to the diffraction intensity of the first diffraction peak of the (111) crystal plane cannot be observed, the melting of the crucible molten layer 13 becomes less likely to occur. It is presumed that the degree of exposure of the (111) crystal face which is hard to be melted by the molten layer of the crucible is more than that of other crystals. On the other hand, when the diffraction peak other than the diffraction peak of the (111) crystal plane can be observed, the melting of the tantalum molten layer 13 is likely to occur, and it is presumed that the crystal is melted toward the surface of the (111) crystal. The degree of exposure of the crystal face other than the (111) crystal plane which is likely to occur in the melting of the layer is increased.

Further, by using the single-crystal tantalum carbide liquid phase epitaxial growth unit 14 of the present embodiment, the epitaxial growth film 20 having hexagonal crystal single crystal yttrium carbide having excellent characteristics can be formed. This is because the (111) crystal plane is equivalent to the (0001) crystal plane of the hexagonal crystal. Therefore, it is considered to be suitable for hexagonal crystal single crystal carbonization by using the crystal material 12 which is exposed on the (111) crystal plane. Epitaxial growth.

Further, as a representative example of the hexagonal single crystal cerium carbide, a single crystal cerium carbide having a crystal polymorph of 4H or 6H can be cited. These crystal polymorphs are 4H or 6H monocrystalline niobium carbide (4H-SiC, 6H-SiC), which has a wide band gap compared to other crystalline polymorphous niobium carbides, and can be realized. Advantages of semiconductor devices with excellent heat resistance.

Further, the polycrystalline niobium carbide film 11c is diffracted by X-rays, and is a diffraction peak corresponding to a polycrystalline 3C-SiC in a corresponding crystal polymorph, and a plurality of first-order diffraction peaks that can be observed correspond to (111) The primary diffraction peak of the crystal face is preferably the main diffraction peak having the maximum diffraction intensity.

The polycrystalline niobium carbide film 11c is diffracted by X-rays, and is a diffraction peak corresponding to polycrystalline 3C-carbonized germanium, and the diffraction peak of the corresponding (111) crystal plane can be observed, and the corresponding 200) a diffraction peak of at least one of a crystal plane, a (220) crystal plane, and a (311) crystal plane is preferable, and it is observed that the (200) crystal plane, the (220) crystal plane, and (311) are respectively observed. The diffraction peak of the crystal face is better. In this case, the growth rate of the monocrystalline niobium carbide epitaxial growth film 20 can be further increased. This is considered to be in the crystal plane other than the (111) crystal plane, and since the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane have particularly high reactivity, the tantalum melt layer 13 The melting becomes easier to occur.

Further, the sum of the intensities of the primary diffraction peaks other than the first diffraction peak of the (111) crystal plane is preferably 10% or more of the total intensity of all the diffraction peaks, and more preferably 20% or more. . In this case, the growth rate of the monocrystalline niobium carbide epitaxial growth film 20 can be further improved.

(Average crystallite diameter of polycrystalline niobium carbide in polycrystalline niobium carbide films 11c, 12c)

The average crystallite diameter calculated from the first diffraction peak observed by X-ray diffraction of the polycrystalline niobium carbide film 11c is observed by X-ray diffraction of the polycrystalline niobium carbide film 12c. The average microcrystal diameter calculated by the secondary diffraction peak is preferably small. According to this structure, the epitaxial growth rate of the monocrystalline niobium carbide can be more effectively improved. This is considered to be because the ratio of the grain boundary which is easily melted in the tantalum molten layer is smaller than that of the polycrystalline niobium carbide film 11c, so that the seed material 12 and the feed material 11 are The ease of melting of the opposing molten layer 13 may be greater.

The polycrystalline niobium carbide film 11c is an average microcrystal diameter calculated from the first diffraction peak of the polycrystalline niobium carbide having a corresponding crystal polymorph of 3C observed by X-ray diffraction. The following are preferred. In this case, the growth rate of the monocrystalline niobium carbide epitaxial growth film 20 can be further improved. In the polycrystalline niobium carbide film 11c, it is considered that the high-reactivity grain boundary occupancy ratio of the polycrystalline niobium carbide crystal is increased, and the melting of the polycrystalline niobium carbide film 11c is more likely to occur.

Further, in the polycrystalline niobium carbide film 11c, by diffraction by X-ray, a first-order diffraction peak corresponding to the (111) crystal plane, a corresponding (200) crystal plane, a (220) crystal plane, and ( 311) at least one diffraction peak in the crystal plane, and (I ₁ /I ₀ ) ^-1 ‧D ² is preferably 10 ⁸ or less.

among them,

I ₀ : the total intensity of the first-order diffraction peak corresponding to the (111) crystal plane, and the total intensity of the first-order diffraction peak corresponding to at least one of the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane Sum,

I ₁ : the total intensity of the first-order diffraction peak corresponding to at least one of the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane,

D: an average microcrystal diameter calculated from a formula of Hall using a primary diffraction peak corresponding to at least one of a (200) crystal plane, a (220) crystal plane, and a (311) crystal plane.

In this case, the growth rate of the monocrystalline niobium carbide epitaxial growth film 20 can be more effectively improved. This is because the ratio of the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane which are relatively high in reactivity in the polycrystalline niobium carbide film 11c is increased, and the average crystallite diameter becomes small. Therefore.

On the other hand, the polycrystalline niobium carbide film 12c is an average microcrystal diameter calculated from the first diffraction peak of the polycrystalline niobium carbide corresponding to the crystal polymorph of 3C, which can be observed by X-ray diffraction. 700 The big one is better. In this case, the growth rate of the monocrystalline niobium carbide epitaxial growth film 20 can be further improved. It is considered that in the polycrystalline niobium carbide film 12c, since the ratio of the high reactivity grain boundary having the polycrystalline niobium carbide crystal is small, the melting of the tantalum molten layer of the polycrystalline niobium carbide film 12c becomes less. It is easy to happen.

(Alignment angle of the (111) crystal plane in the polycrystalline niobium carbide films 11c and 12c)

Among the (111) crystal planes observed by X-ray diffraction, the ratio of the alignment angle of 67.5° or more is preferable to the polycrystalline niobium carbide film 11c, which is smaller than the polycrystalline niobium carbide film 11c. . In this case, the epitaxial growth rate of the monocrystalline niobium carbide can be more effectively improved. The degree of exposure of the surface having a lower (111) crystal plane stability to the crystal of the (111) crystal plane is higher than that of the polycrystalline niobium carbide film 12c, and the polycrystalline niobium carbide film 11c becomes higher. Therefore, it is considered that the easiness of melting of the opposite molten layer 13 between the seed material 12 and the feed material 11 can be made larger.

From the viewpoint that the epitaxial growth rate of the monocrystalline niobium carbide can be more effectively improved, in the (111) crystal plane observed by the X-ray diffraction of the polycrystalline niobium carbide film 11c, the alignment angle is 67.5° or more. The occupancy ratio is preferably less than 80%. Further, in the (111) crystal plane of the polycrystalline niobium carbide film 12c which is observed by X-ray diffraction, the ratio of the alignment angle of 67.5° or more is preferably 80% or more.

Further, in the present embodiment, the absolute amount of movement from the 972 cm ^-1 of the L0 peak of the polycrystalline niobium carbide having a crystal polymorph of 3 C can be observed by Raman spectroscopic analysis in which the excitation wavelength is set at 532 nm. The value is such that the polycrystalline niobium carbide film 11c constituting the surface layer of the feed substrate 11 is made smaller than the polycrystalline niobium carbide film 12c constituting the surface layer of the seed substrate 12 to form the seed substrate 12 and the feed substrate. 11. Therefore, the melting of the tantalum molten layer 13 by the seed crystal substrate 12 becomes more difficult to occur, and on the other hand, the melting of the tantalum molten layer 13 of the feed material 11 becomes easier. As a result, the epitaxial growth film of the monocrystalline niobium carbide can be suitably formed at a faster growth rate.

Further, the absolute value of the movement amount of the L0 peak from 972 cm ^{-1 is} the polycrystalline niobium carbide film 11c constituting the surface layer of the feed substrate 11, and is changed from the polycrystalline niobium carbide film 12c constituting the surface layer of the seed crystal substrate 12. The seed substrate 12 and the feed substrate 11 are formed in a smaller manner. Therefore, it is more suitable for epitaxial growth of hexagonal crystal single crystal carbonized germanium. It is considered that the denseness of the surface layer of the seed crystal substrate 12 is high, and most of the crystal faces exposed on the surface of the surface layer are in a shape similar to the (0001) crystal plane of the hexagonal crystal.

From the liquid phase epitaxial growth of the monocrystalline silicon carbide of more improving the viewpoint, the absolute value of the peak 11 of the L0 feed amount of movement of the substrate from the 972cm ^-1, and is preferably less than 4cm ^-1. In this case, since the melting of the opposite molten layer 13 by the feed substrate 11 becomes easier, it is considered that the liquid crystal epitaxial growth rate can be further improved.

Further, the absolute value L0 peaks 12 of the seed crystal substrate from the amount of movement of 972cm ^-1, who is more preferably at 4cm ^-1. In this case, since the melting of the opposite molten layer 13 by the seed substrate 12 becomes less easy, it is considered that the liquid crystal epitaxial growth rate can be further improved. Further, the amount of movement L0 from the 972cm ^-1 peak in the seed crystal substrate 12, is more preferably by at 4cm ^-1.

In the feed substrate 11, the half value width of the L0 peak is preferably 7 cm ^-1 or more. At this time, the epitaxial growth rate of the monocrystalline niobium carbide can be further improved. This is because the half value of the L0 peak is larger, the crystallinity of the polycrystalline niobium carbide in the surface layer is lowered, or the impurity concentration is increased, so that it is considered that the melting of the surface layer is more likely to occur.

On the other hand, in the seed crystal substrate 12, the half value width of the L0 peak is preferably 15 cm ^-1 or more. In this case, the epitaxial growth rate of the monocrystalline niobium carbide can be further improved. This is because the half value width of the L0 peak is smaller, and the crystallinity of the polycrystalline niobium carbide in the surface layer of the seed crystal substrate 12 becomes higher, or the impurity concentration becomes lower, and it is considered that the melting of the surface layer of the seed crystal substrate 12 becomes It is less likely to happen.

Therefore, it is preferable that the half value of the L0 peak in the feed substrate 11 is wider than the half value width of the L0 peak in the seed substrate 12.

Further, in the above embodiment, the feed substrate 11 and the seed crystal substrate 12 are each constituted by the support members 11b and 12b and the polycrystalline niobium carbide films 11c and 12c. However, the present invention is not limited to this structure. For example, as shown in FIGS. 4 and 5, the feed substrate 11 and the seed substrate 12 may each be formed of a polycrystalline niobium carbide substrate containing polycrystalline niobium carbide.

Further, the production of the tantalum carbide substrate can be carried out, for example, by coating a polycrystalline niobium carbide on a graphite substrate by a CVD method, and then mechanically or chemically removing the graphite. Further, the tantalum carbide substrate may be produced by reacting a graphite material with a tantalum gas and converting the graphite material into tantalum carbide. Further, the tantalum carbide substrate can be produced by sintering a high temperature of 1600 ° C or higher by adding a sintering aid to the tantalum carbide powder.

Hereinafter, the present invention will be further described based on specific examples, but the present invention is not limited by the following specific examples.

(production example 1)

A graphite material (15 mm × 15 mm × 2 mm) made of a high-purity isotropic graphite material having a bulk density of 1.85 g/cm ³ and an ash content of 5 ppm or less was used as a substrate, and the substrate was placed in a CVD reaction. In the apparatus, a polycrystalline niobium carbide film having a thickness of 30 μm was formed on a substrate by a CVD method to prepare a sample 1. Further, as a material gas, ruthenium tetrachloride and propane gas were used, and film formation was carried out at normal pressure at 1200 °C. The film formation speed was set at 30 μm/h.

(Production Example 2)

A polycrystalline niobium carbide film having a thickness of 50 μm was formed on the surface of the graphite material in the same manner as in the above-described production example except that the reaction temperature was set to 1400 ° C and the film formation rate was set to 60 μm/h. .

(production example 3)

Except that the reaction temperature was set to 1250 ° C, the film formation rate was set to 10 μm/h, and the use of CH ₃ SiCl _{3 in} place of ruthenium tetrachloride, the same operation as in the above Production Example 1 was carried out to form a surface of 50 μm on the surface of the graphite material. The carbonized ruthenium film was formed into a sample 3.

(production example 4)

Except that dichlorosilane (SiH ₂ Cl ₂ ) and acetylene were used in place of ruthenium tetrachloride and propane, the reaction temperature was set to 1300 ° C, and the film formation rate was set to 10 μm/h, and the same operation as in the above production example 1 was carried out. A 50 μm polycrystalline niobium carbide film was formed on the surface of the graphite material to prepare a sample 4. Meanwhile, in Sample 4, the thickness of the polycrystalline niobium carbide film was about 1 mm.

(X-ray diffraction measurement)

X-ray diffraction was performed on the surface layers of the samples 1 to 4 produced as described above. Further, the X-ray diffraction was performed using Ulutima manufactured by Nippon Science Co., Ltd. The measurement results are shown in Fig. 6.

As shown in Fig. 6, in the samples 1, 2, the diffraction peak corresponding to the (111) crystal plane (2θ = 35.6 °) can be observed, and the diffraction peaks of the crystal plane other than the corresponding (111) crystal plane can be observed. . Specifically, in the samples 1 and 2, in addition to the diffraction peak (2θ=35.6°) of the corresponding (111) crystal plane, the diffraction peak corresponding to the (200) crystal plane can be observed (2θ=41.4°). Corresponding to (160) the diffraction peak of the crystal plane (2θ=60.0°) and the diffraction peak of the (311) crystal plane (2θ=71.7°).

On the other hand, in the samples 3 and 4, the first diffraction peak corresponding to the (111) crystal plane (2θ = 35.6 °) can be observed, and the (222) crystal plane of the higher-order diffraction peak corresponding thereto can be observed. The peak of the radiation (2θ = 75.5°) is not observed, but the first diffraction peak having an intensity corresponding to 10% or more of the first-order diffraction peak intensity of the (111) crystal plane cannot be observed.

In Table 2 below, the relative intensities of the first diffraction peaks corresponding to the respective crystal faces when the intensity of the first diffraction peak of the (111) crystal plane is taken as 100 in the samples 1 to 4.

(calculation of average microcrystalline diameter)

Based on the results of the X-ray diffraction measurement described above, the average crystallite diameters of the samples 1 to 4 were calculated using the formula of Hall. Further, in the calculation, data on the diffraction peaks of the (111) crystal plane, the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane are used. The results are shown in Table 3 below.

From the results shown in Table 3 above, in samples 1, 2, the average crystallite diameter was 700. Following, in more detail, at 500 Below, on the other hand, in samples 3, 4, the average crystallite diameter is 700 Big, in more detail, at 1000 the above.

((111) Orientation evaluation of crystal faces)

Next, regarding the samples 1 to 4, as shown in Fig. 7, the angle of the diffraction peak of the (111) plane was measured while rotating the sample. The results are shown in Figures 8 to 11. Further, in the graphs shown in Figs. 8 to 11, the horizontal axis is the alignment angle (α) shown in Fig. 7. The vertical axis is the intensity.

Further, in Table 4 below, the ratio of the intensity integral value of the region where the alignment angle (α) is 67.5° or more to the intensity integral value of the entire region with the alignment angle (α) of 15° to 90° is shown ((Orientation) The angle (α) is an intensity integral value of a region of 67.5° or more / ((the alignment angle (α) is an intensity integral value of the entire region in the range of 15° to 90°). Further, ((the alignment angle (α) is 67.5°) The intensity integral value of the above region / (the integral integral value of the entire region in the angle of alignment (α) from 15° to 90°) is among the (111) crystal faces observed by X-ray diffraction, which corresponds to the alignment The ratio of the occupancy of the angle of 67.5 ° or more.

As shown in the eighth and ninth figures and the above-mentioned Table 4, in the samples 1 and 2, a large intensity distribution exists in the region where the alignment angle (α) is less than 67.5°, and is in the (111) crystal plane. In the case where the alignment angle (α) is 67.5° or more, the ratio is less than 80%. On the other hand, in the samples 3 and 4, as shown in the 10th and 11th and the above-mentioned Table 4, there is no large intensity distribution in the region where the alignment angle (α) is less than 67.5°, and the alignment is performed. The ratio of the angle (α) of 67.5° or more is 80% or more.

(Raman spectroscopic analysis)

Raman spectroscopic analysis of the surface layers of Samples 1 to 4 described above was carried out. Further, in the Raman spectroscopic analysis, an excitation wavelength of 532 nm was used, and the measurement result is shown in Fig. 12.

Next, from the measured results shown in FIG. 12, the amount of movement is obtained (Δω) 972cm ^-1 in Sample 1-4 L0 from the peak, the half width of the peak value L0 (FWHM). The results are shown in Figure 13.

As shown in Fig. 13, the absolute values of Δω of the samples 3 and 4 were 4 cm ^-1 or more, and the FWHM was 7 cm ^-1 or more. On the other hand, the FWHM of the samples 1 and 2 was 7 cm ^-1 or more as in the samples 3 and 4, but the absolute value of Δω was less than 4 cm ^-1 .

(Evaluation of growth rate of liquid crystal epitaxial growth film of monocrystalline niobium carbide)

According to the liquid phase epitaxial growth method described in the above embodiment, the samples 1 to 4 were used as a feed substrate, and a single crystal yttrium carbide epitaxial growth film 20 was produced under the following conditions. Then, the thickness of the monocrystalline lanthanum carbide epitaxial growth film 20 was measured by observing the cross section of the tantalum carbide epitaxial growth film 20 using an optical microscope. The growth rate of the monocrystalline lanthanum carbide epitaxial growth film 20 was determined by dividing the measured thickness by the time during which the bismuth carbide epitaxial growth was performed.

The results are shown in Figures 14 and 15. Further, in FIGS. 14 and 15, the vertical axis represents the growth rate of the monocrystalline niobium carbide epitaxial growth film 20, and the horizontal axis represents the reciprocal (1/L) of the thickness (L) of the tantalum melt layer 13.

From the results shown in Figs. 14 and 15, the polycrystalline niobium carbide film 11c constituting the surface layer of the feed substrate 11 is diffracted by X-rays, and is a crystal polymorph to a diffraction peak corresponding to polycrystalline 3C-SiC. In the case where the diffraction peaks of the corresponding (111) crystal plane are observed, and the samples 1 and 2 of the diffraction peaks other than the diffraction peaks corresponding to the (111) crystal plane are observed, the monocrystalline niobium carbide is epitaxially grown. The growth rate of the film 20 is high. On the other hand, the polycrystalline niobium carbide film 11c constituting the surface layer of the feed substrate 11 is diffracted by X-rays, and the crystal polymorph is a diffraction peak corresponding to polycrystalline 3C-SiC, and only the corresponding correspondence can be observed (111). The diffraction peak of the crystal plane, and the intensity of 10% or more of the first-order diffraction peak intensity corresponding to the (111) crystal plane, cannot be observed except for the first-order diffraction peak corresponding to the (111) crystal plane. In the case of the samples 3 and 4 of the secondary diffraction peak, the growth rate of the monocrystalline niobium carbide epitaxial growth film 20 is low. From this fact, it is understood that the melting of the tantalum molten layer 13 by the samples 3 and 4 is not easy to occur.

(Measurement conditions for the growth rate of the monocrystalline niobium carbide epitaxial growth film 20)

Feeding substrate: a silicon carbide substrate having a crystal shape of 4H

Ambient gas pressure: 10 ^-6 to 10 ^-4 Pa

Ambient gas temperature: 1900 ° C

(Example)

The sample 1 prepared above was used as the feed substrate 11, and the sample 3 prepared as described above was used as the seed substrate 12, and liquid phase epitaxial growth of monocrystalline niobium carbide was carried out under the same conditions as the growth rate evaluation test described above. experiment. Thereafter, a surface of the sample 3 as the seed crystal substrate 12 was subjected to a photographic scanning electron microscope (SEM) image. The SEM image of the surface of the sample 3 is shown in Fig. 16. It can be seen from the image shown in FIG. 16 that, in the case of the feed substrate 11, the X-ray diffraction of the surface layer is used as the diffraction peak of the polycrystalline 3C-SiC corresponding to the crystal polymorphism, and the observable correspondence is used. 111) The diffraction peak of the crystal face, and the samples 1 and 2 of the diffraction peak other than the diffraction peak corresponding to the (111) crystal plane are observed, and in the case of the seed substrate 11, the X-ray winding by the surface layer The first diffraction peak of polycrystalline 3C-SiC is used as the corresponding crystal polymorph, and the first diffraction peak of the corresponding (111) crystal plane can be observed, and the first winding with the corresponding (111) crystal plane cannot be observed. A sample 3 of another primary diffraction peak having a diffraction intensity of a peak of 10% or more is obtained, whereby a hexagonal crystal monocrystalline niobium carbide epitaxial growth film can be obtained.

(Comparative example)

The sample 1 prepared above was used as a feed substrate, and the sample 2 prepared above was used as a seed crystal substrate, and a liquid crystal epitaxial growth experiment of monocrystalline carbonized niobium was carried out under the same conditions as the above-described growth rate evaluation test. Thereafter, a scanning electron microscope (SEM) image on the surface of the sample 2 as a seed crystal substrate was irradiated. The SEM image of the surface of the sample 2 is shown in Fig. 17. It can be seen from the image shown in Fig. 17 that the polycrystalline niobium carbide film is X-ray diffraction, and the corresponding crystal polymorph is polycrystalline 3C-SiC. By diffracting the peak, it is possible to observe the first diffraction peak of the corresponding (111) crystal plane, and to observe the diffraction intensity of the diffraction intensity of 10% or more with the first diffraction peak of the corresponding (111) crystal plane. In the case where the sample 2 of the diffraction peak was used as a seed crystal substrate, almost no epitaxial growth was performed, and it was not suitable to obtain a hexagonal crystal monocrystalline niobium carbide epitaxial growth film.

10. . . container

11. . . Feed substrate

11a. . . Main face

11b. . . Support material

11c. . . Polycrystalline niobium carbide film

12. . . Seed substrate

12a. . . Main face

12b. . . Support material

12c. . . Polycrystalline niobium carbide film

13. . .矽melting layer

14. . . Monocrystalline carbonized niobium liquid phase epitaxial growth unit

20. . . Monocrystalline niobium carbide epitaxial growth film

Fig. 1 is a schematic view for explaining a method of epitaxial growth of monocrystalline niobium carbide according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view showing a feed substrate in an embodiment of the present invention.

Fig. 3 is a schematic cross-sectional view showing a seed crystal substrate in an embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view showing a feed substrate in a modification.

Fig. 5 is a schematic cross-sectional view showing a seed crystal substrate in a modification.

Figure 6 is an X-ray diffraction chart of Samples 1 to 4.

Fig. 7 is a schematic view for explaining the method of measuring the orientation of the (111) crystal face.

Fig. 8 is a view showing the orientation of the (111) crystal plane in the sample 1.

Fig. 9 is a view showing the orientation of the (111) crystal plane in the sample 2.

Fig. 10 is a view showing the orientation of the (111) crystal plane in the sample 3.

Fig. 11 is a view showing the orientation of the (111) crystal plane in the sample 4.

Fig. 12 is a graph showing the results of surface Raman spectroscopic analysis of samples 1 to 4.

Figure 13 shows a sample of from 1 to 4, the amount of movement L0 peak of 972 cm ^-1 (Δω), and the half width value L0 (FWHM) of FIG.

Fig. 14 is a graph showing the growth rate of the epitaxial growth film of monocrystalline niobium carbide in the samples 1, 2, and 4.

Fig. 15 is a graph showing the growth rate of the epitaxial growth film of monocrystalline niobium carbide in the samples 3 and 4.

Fig. 16 is a SEM photograph of the seed crystal substrate (Sample 3) after the liquid crystal epitaxial growth experiment in the examples.

Fig. 17 is a SEM photograph of the seed crystal substrate (Sample 2) after the liquid crystal epitaxial growth experiment in the comparative example.

10. . . container

11. . . Feed substrate

11a. . . Main face

12. . . Seed substrate

12a. . . Main face

13. . .矽melting layer

14. . . Monocrystalline carbonized niobium liquid phase epitaxial growth unit

20. . . Monocrystalline niobium carbide epitaxial growth film

Claims (23)

A unit for liquid crystal epitaxial growth of monocrystalline niobium carbide, which is a unit for seed crystals and feed materials used in a liquid crystal epitaxial growth method of monocrystalline niobium carbide by epitaxial stabilization solvent epitaxy, The feed material has a surface layer comprising polycrystalline niobium carbide having a crystal polymorph of 3C, and X-ray diffraction of the surface layer of the feed material is used as a diffraction peak corresponding to a polycrystalline niobium carbide having a crystal polymorph of 3C. Observing a diffraction peak corresponding to the (111) crystal plane and a diffraction peak other than the diffraction peak corresponding to the (111) crystal plane; the foregoing crystal material has a surface layer containing a polycrystalline niobium carbide having a crystal polymorph of 3C By using the X-ray diffraction of the surface layer of the above-mentioned crystal material as the diffraction peak corresponding to the polycrystalline niobium carbide having a crystal polymorph of 3C, the first diffraction peak of the corresponding (111) crystal plane can be observed, and the observation cannot be observed. The other one-order diffraction peak corresponding to the diffraction intensity of 10% or more of the diffraction intensity of the first-order diffraction peak of the (111) crystal plane. The single crystal silicon carbide liquid phase epitaxial growth unit according to claim 1, wherein the X-ray diffraction of the surface layer of the feed material corresponds to the first diffraction of the (111) crystal plane. The peak system has a main diffraction peak having the largest diffraction intensity among the first diffraction peaks corresponding to the above-mentioned polycrystalline niobium carbide having a crystal polymorph of 3C. The single crystal silicon carbide liquid phase epitaxial growth unit according to claim 1, wherein the diffraction of the (111) crystal surface is observed in the X-ray diffraction of the surface layer of the feed material. The diffraction peaks other than the peaks contain the corresponding (200) crystal plane, (220) crystal plane, and (311) A diffraction peak of at least one of the crystal faces. The single crystal silicon carbide liquid phase epitaxial growth unit according to claim 3, wherein the diffraction of the (111) crystal plane is observed in the X-ray diffraction of the surface layer of the feed material. The diffraction peaks other than the peaks contain diffraction peaks corresponding to the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane. The single crystal silicon carbide liquid phase epitaxial growth unit according to any one of claims 1 to 4, wherein the (111) crystal is corresponding to the X-ray diffraction of the surface layer of the feed material. The sum of the intensity of the first-order diffraction peaks other than the first-order diffraction peak is 10% or more of the total of the first-order diffraction peak intensities. The single crystal silicon carbide liquid phase epitaxial growth unit according to any one of claims 1 to 4, wherein the feed material and the seed crystal system respectively have a crystal polymorph of 3C. The surface layer of the crystalline niobium carbide can be observed by X-ray diffraction of the surface layer of the feed material, and at least one of the (111) crystal plane, the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane can be observed. The average microgravity diameter ratio calculated from the primary diffraction peak of at least one of the at least one of the feed materials, the average micro-calculation calculated from the first diffraction peak of the at least one of the foregoing crystal materials. The crystal diameter is still small. The single crystal silicon carbide liquid phase epitaxial growth unit according to claim 6, wherein the corresponding crystal polymorph is 3C polycrystal observed from the X-ray diffraction of the surface layer of the feed material. The average microcrystal diameter calculated from the first diffraction peak of tantalum carbide is 700 Å or less. The single crystal silicon carbide liquid phase epitaxial growth unit according to claim 7, wherein the first (111) crystal plane is observed by the X-ray diffraction of the surface layer of the feed material. a first-order diffraction peak of at least one of a radio wave peak and a corresponding (200) crystal plane, a (220) crystal plane, and a (311) crystal plane, and the intensity of the first-order diffraction peak corresponding to the (111) crystal plane is The sum of the total intensity of the primary diffraction peak corresponding to at least one of the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane is I ₀ , which corresponds to the (200) crystal plane, (220). The total intensity of the primary diffraction peak of at least one of the crystal surface and the (311) crystal plane is I ₁ and corresponds to at least one of the (200) crystal plane, the (220) crystal plane, and the (311) crystal plane. When the average microcrystal diameter calculated by the first diffraction peak is D, (I ₁ /I ₀ ) ^-1 . D ² is below 10 ⁸ . The liquid crystal epitaxial growth unit for single crystal cerium carbide according to claim 6, wherein the corresponding crystal polymorph is 3C polycrystal which can be observed from the X-ray diffraction of the surface layer of the foregoing crystal material. The average microcrystal diameter calculated from the first diffraction peak of tantalum carbide is larger than 700 Å. The monocrystalline niobium carbide liquid phase epitaxial growth unit according to any one of claims 1 to 4, wherein the (111) crystal plane alignment is observed by X-ray diffraction of the surface layer In the case where the angle is 67.5° or more, the feed material is smaller than the above-mentioned seed crystal. The single crystal silicon carbide liquid phase epitaxial growth unit according to claim 10, wherein the X-ray diffraction of the surface layer of the feed material is In the observed (111) crystal plane, the ratio of the alignment angle of 67.5° or more was less than 80%. The monocrystalline silicon carbide liquid phase epitaxial growth unit according to claim 10, wherein the alignment angle of the (111) crystal plane observed by X-ray diffraction of the surface layer of the foregoing crystal material The occupancy ratio of those of 67.5° or more is 80% or more. The monocrystalline niobium carbide liquid phase epitaxial growth unit according to any one of claims 1 to 4, wherein, in the feed material and the foregoing crystal material, the excitation wavelength is determined For Raman spectroscopic analysis at 532 nm, it is possible to observe the L0 peak derived from the polycrystalline niobium carbide having a crystal polymorph of 3 C in the surface layer, and the absolute value of the movement amount of the L0 peak from 972 cm ^-1 is the above-mentioned feed material side. It is smaller than the above-mentioned crystal. The patentable scope of the application as item 13 of monocrystalline silicon carbide phase epitaxial growth unit, wherein the feed material into the peak of L0 from the absolute value of the moving amount is less than 972cm ^-1 4cm ^-1. The patentable scope of the application as item 13 of monocrystalline silicon carbide phase epitaxial growth unit, wherein the seed crystal material of the L0 from the absolute value of the peak of the amount of movement of 4cm ^-1 972cm ^-1 or more. The single crystal silicon carbide liquid phase epitaxial growth unit according to claim 13, wherein the half value width of the L0 peak in the feed material is 7 cm ^-1 or more. The monocrystalline silicon carbide liquid phase epitaxial growth unit according to claim 13, wherein the half value width of the L0 peak in the crystal material is 15 cm ^-1 or less. The single crystal silicon carbide liquid phase epitaxial growth unit according to any one of the first to fourth aspect, wherein the surface layer contains crystals in at least one of the feed material and the seed crystal material. The polymorphic 3C polycrystalline niobium carbide is used as a main component. The monocrystalline silicon carbide liquid phase epitaxial growth unit according to claim 18, wherein in the at least one of the feed material and the seed crystal, the surface layer is substantially 3C from a crystal polymorph. Made of polycrystalline niobium carbide. The single crystal silicon carbide liquid phase epitaxial growth unit according to any one of claims 1 to 4, wherein at least one of the feed material and the seed crystal material is provided with a support material and formed A polycrystalline niobium carbide film formed on the above support material. The monocrystalline niobium carbide liquid phase epitaxial growth unit according to claim 20, wherein the polycrystalline niobium carbide film has a thickness in the range of 30 μm to 800 μm. The single crystal silicon carbide liquid phase epitaxial growth unit according to any one of claims 1 to 4, wherein at least one of the feed material and the seed crystal material comprises a crystal polymorph It is composed of a 3C polycrystalline niobium carbide polycrystalline carbonized coffin. A method for liquid crystal epitaxial growth of a single crystal cerium carbide according to any one of claims 1 to 22, which is a liquid crystal epitaxial growth unit according to any one of claims 1 to 22. The liquid crystal epitaxial growth method of the monocrystalline niobium carbide is separated from the surface layer of the foregoing feed material by the surface layer of the foregoing crystal material The molten layer is heated and heated in a relatively opposed state, and monocrystalline niobium carbide is epitaxially grown on the surface layer of the above-mentioned seed crystal.